The number of international refugees climbed from below 5 million in the 1950s, 1960s, and 1970s to a peak of close to 18 million in the early 1990s, but it has since declined to just above 10 million.

The number of climate-displaced persons is generally expected to rise in coming years as extreme weather events become more frequent and intense and as droughts, desertification, sea-level rise, and glacier melt become more prominent phenomena.

For reasons that range from warfare and persecution to natural disasters and development projects, an estimated 92.6 million people were forcibly displaced in 2012, either inside their home countries or across a border.

International refugees under the care of the UN High Commissioner for Refugees (UNHCR) numbered 10.5 million, and there are also close to 1 million asylum seekers worldwide. Internally displaced persons (IDPs)—at 28.8 million—outnumber international refugees by a significant margin. People displaced by natural hazards—typically also displaced inside their own countries but seen as a separate category since, unlike IDPs, they are not victims of human actions—ran to more than 32 million in 2012, but this number varies considerably from year to year. In addition, a large number of people are displaced by ill-considered development projects. No firm numbers exist, but the World Disasters Report 2012 offers a rough guess of 15 million such individuals.

Over time, the trends in refugee and IDP numbers have diverged substantially. The number of international refugees climbed from below 5 million in the 1950s, 1960s, and 1970s to a peak of close to 18 million in the early 1990s, but it has since declined to just above 10 million. Given the unresolved Israeli-Palestinian conflict, the number of Palestinian refugees has been rising over the decades from less than 1 million in 1950 to about 5 million today. For internally displaced persons, only a much shorter time series of data is available. Following a rapid rise and then decline in the 1990s, their numbers have risen steadily to record levels.

During 2012, some 1.1 million people were newly displaced across international borders—principally from the Democratic Republic of the Congo (DRC), Mali, Somalia, Sudan, and Syria. This is equivalent to about 3,000 persons each day, and it is the highest annual figure since 1999. Meanwhile, only 526,000 refugees returned to their home countries voluntarily during 2012—primarily to Afghanistan, Côte d’Ivoire, and Iraq.

Around 6.5 million people were newly displaced inside their own countries during 2012, far surpassing returnees and thus raising the total number of IDPs to the highest figure since comparable data were recorded in 1989. Colombia has the largest number of IDPs, estimated at between 4.9 million and 5.5 million, followed by Syria (3 million), the DRC (2.7 million), Sudan (2.2 million), and Iraq (2.1 million). Regionally, sub-Saharan Africa has the largest number of IDPs at 10.4 million, followed by the Middle East and North Africa (6 million), the Americas (5.8 million), South and Southeast Asia (4.1 million), and Europe/Central Asia (2.5 million).

Unlike international refugees, many IDPs do not receive protection and assistance, often because their own governments or armed opposition groups block access to them. Lack of safety for aid workers and inadequate transport and logistical infrastructure are additional factors. UNHCR has had an expanded role in caring for IDPs, and the number that agency has under its care has risen from 4–5 million people a decade ago to some 17.7 million people at the end of 2012—about 60 percent of the worldwide IDP population.

UNHCR’s responsibility has steadily expanded over the years, reflecting greater complexity in the types and patterns of displacement around the world. This concerns not only IDPs but also stateless people as well as people affected by major natural disasters. The number of people forced to flee in the face of rapid-onset natural disastersfluctuates strongly from year to year, depending, of course, on the severity and frequency of disasters. The figures include the impacts of floods, storms, earthquakes, and wildfires but not droughts, which also may generate large movements of people. In some cases, people are displaced for prolonged periods of time, especially when there are recurring disasters.

The number of climate-displaced persons is generally expected to rise in coming years as extreme weather events become more frequent and intense and as droughts, desertification, sea-level rise, and glacier melt become more prominent phenomena. The International Organization for Migration, for example, has suggested that in a 4 degrees Celsius world, the commonly cited estimate of 200 million people displaced by climate change by 2050 could “easily be exceeded.” But it is impossible to make any reliable projections about how many people may be uprooted due to climate change in coming years and decades. There are too many unknowns to be able to predict the scale of population movements to come, let alone their direction, destination, and timing.

Further highlights from the report:

Long-term international migrants—people who decide to live outside their home country for a year or longer—are estimated at 214 million, and internal migrants may number as many as 740 million.

Afghanistan (at 2.6 million) remains the leading country of origin for refugees, followed by Somalia (1.1 million), Iraq (746,000), Syria (729,000), and Sudan (569,000).

In 2012, three quarters of all disaster-related displacements took place in just four countries: more than 9 million people in India, 6.1 million in Nigeria, more than 5.5 million in China, and 3.7 million in the Philippines. Hurricane Sandy, by comparison, displaced 1.1 million people in the United States and Cuba.